| 摘要 |
A drive mechanism serving for displacing window panes, sliding roofs and the like of motor vehicles is provided. The drive mechanism comprises a drive motor with an output shaft which drives the worm shaft (10) of a worm gear. The worm wheel (12) of the worm gear forms a first clutch half mounted freely rotatably and having on the end face receptacles for dogs (28) which belong to a second clutch half. The second clutch half is connected firmly to the output shaft (18) of the worm gear. The dogs (28) project from the second clutch half in the axial direction of the output shaft (18). Arranged coaxially relative to the axis of rotation of the worm wheel (12) within a housing (14) surrounding the worm gear is a cylindrical wall (34) which is fixed to the frame and against which a helical spring bears with slight prestress. The ends of the spring wire (42) are directed radially away from the wall and form extensions which interact with shoulders of the worm wheel (12) and with stops of the second clutch half (48) respectively. The shoulders and the stops engage on the extensions (42) on the opposite sides in each case. When the force flux comes from the worm wheel, the spring is released from the wall and the mechanism can operate. But when the force flux arrives at the second clutch half from the output shaft, the spring is braked against the wall, so that a movement of the mechanism is not possible from the part to be displaced. <IMAGE> |
